I think this is pretty clearly the case.
It really doesn't seem that credible that you can have many women being very successful in certain scientific fields, but all of a sudden when it comes to physics the whole thing is so sexist that women can't get a look in. Especially when we consider that the women who do pursue it and are suited can do quite well.
Some give the explanation that it is because girls are not encouraged to go into those areas, but then, we see all kinds of efforts to do just that indifferent places, and it doesn't seem to make much difference.
One area where I think there is a kind of gap is that in my observation, women in the sciences will tend somewhat toward areas that are more easily combined with balanced home life. So my dh works in the civil service as a scientist. Women aren't really dominant in his area, but there are a lot of them in government sections. His view is they tend to go forthosejobs because they have reasonable, regular hours and good benefits, maternity leave, and so on.
I don't really see that as a bad thing either though. I don't think having every work sector completely mirroring the population is all that important.